Was ever a sprint champion better named? Lightning bolt. Usain St Leo Bolt: the fastest man on planet Earth. Before he triumphed with a gold medal in 2008, only track diehards had heard of him. Now the 25-year-old Jamaican is famous worldwide. In spite of his fame he remains heroically down to earth and relaxed. He loves reggae and "lyrically active" (verbally inventive) Jamaican dancehall DJs. He stands at 6ft 5ins. He has survived a car crash. Yet he will not consider himself a legend unless he rules in London next week, as he did in Beijing four years ago.

Jamaica loves a hero, and no Jamaican is more heroic than Bolt. Born in 1986 on the island's rural north coast, he grew up poor. His parents ran a grocery store selling bottles of rum and cigarettes. By the age of 12, Bolt was the school's fastest 100m sprinter; now he is a three-time Olympic gold medallist. All kinds of Jamaicans will be rooting for him next week at the starting blocks. Black, white, brown and yellow; vested interests, professionals, businesspeople; all will be joined in optimism about their sporting hero and Jamaica's own future.

In an island riven by gang warfare and poverty, Bolt will help to rally Jamaicans to the black, gold and green of the national flag. As every Jamaican knows, the green is symbolic of hoped-for rebirth and the black a recognition of continental Africa. For years, Jamaica's African slave heritage was the dark area of self-denial in the national psyche. (To a degree, it still is.) Bolt gives an immense sense of pride not only to Jamaicans living in Jamaica, but to diaspora Jamaicans in the United States and the UK. This August, as Jamaica prepares to celebrate 50 years of independence from Britain, Usain Bolt will be a reason to jump (even sprint) for joy. An estimated 1 million people have applied for tickets to watch him run in a race that will be over in less than 10 seconds. To Di World!

• Ian Thomson is author of the prize-winning book about Jamaica, The Dead Yard